Electrical switch components and switches formed thereby

ABSTRACT

This invention relates to electrical switch components for snap action mechanisms particularly of the butterfly type and utilizes a second class lever system wherein the tension spring is attached outboard of the contact portions to an integral shear formed attachment strut to afford large movement differential, high leverage contact forces and stability. The integral attachment strut means for the one piece switchblade and contact member is reversely curved for mechanical wear properties in attachment of the end of the tension spring and is proportioned and located for maintenance of dimensional stability to the curved spaced contact portions. There is use of the space intermediate the contacts for location and attachment of the tension member, the contacts being spaced portions of the end of the switchblade which is of a generally cylindrical form. The switches also have a &#39;&#39;&#39;&#39;rolling sleeve&#39;&#39;&#39;&#39; sealing means, dual use of the terminal slot for mounting and as a rotation preventing keyway and also a common terminal means is resiliently mounted in situ in a manner to form an open sided solder pot. The two pole four circuit version of the mechanism has an energy storing resilient donut mechanism for assuring simultaneity of both sets of bridging contacts.

United States Patent [72] Inventor John O. Roeser FOREIGN PATENTS Arlmgm8181115, 52,705 12/1968 East Germany 200/168 1 1 pp 778,626 1,284,6251/1962 France 200/168 0 [22] Filed Nov. 25, 1968 1,446,479 6/1966 France200/ 168 G [451 Pmmed E 621,328 4 1949 Great Britain.. 200/168 G ux [731Asslgnee EnglneeFngJnc- 1,088,083 /1967 Great Britain.. 200/67 B uxCarpentersvllleJll. 1,263,228 5/1961 France 200/67 B UX 1,330,289 5/1963France 200/670 UX [54] ELECTRICAL SWITCH COMPONENTS AND PrimaryExaminer-David Smith, Jr.

SWITCHES FORMED THEREBY Attorneys-Robert D. Silver and Dawson, Tilton,Fallon and Claims, 27 Drawing Figs. Lungmus 52 US. Cl 200/67 B,

51 I ZOO/166 ZOO/168 6100/76 ABSTRACT: This invention relates toelectrical switch com- Fntid ..H01h 13/28 ponems for Snap acfionmechanisms particularly f h b 1e 0 ea 200/67, 67 terfly type andutilizes a Second class lever system wherein the 168 166 67 D; 339/220tension spring is attached outboard of the contact portions to 1561803285;?1122?;niiit fii tflflgijlt81235215 UNITED STATES PATENTS bility.The integral attachment strut means for the one piece 2,360,128 10/ 1944l-lausler 200/67 D Switchblade and contact member is reversely curvedfor 2,519,297 8/1950 Stump, Jr. et al. 200/76 mechanical wear propertiesin attachment of the end of the 2,884,503 4/1959 Connelly 200/67Dtension spring and is proportioned and located for main- 3,497,649 9 a200/67 D tenance of dimensional stability to the curved spaced contact2,187,379 1/1940 l-lensel et al. 200/6 C UX portions. There is use ofthe space intermediate the contacts 1,645,528 10/1927 Gordon 200/67 B UXfor location and attachment of the tension member, the con- 1,666,9254/1928 Benjamin 200/67 BUX tacts being spaced portions of the end of theswitchblade 1,944,522 1/ 1934 Miller et al.. 200/67BUX which is of agenerally cylindrical form. The switches also 2,790,865 4/1957 Cherry,Jr 200/67 B UX have a rolling sleeve" sealing means, dual use of theterminal 2,840,657 6/1958 Roeser 200/67 B UX slot for mounting and as arotation preventing keyway and also 2,913,634 11/1959 Scov1lle...339/220 a common terminal means is resiliently mounted in situ in a3,031,548 4/ 1962 Robinson 200/67 B UX manner to form an open sidedsolder pot. The two pole four 3,073,923 1/ 1963 Anderson et 200/67 B UXcircuit version of the mechanism has an energy storing 3,106,436 10/1963Weiss 339/220 resilient donut mechanism for assuring simultaneity ofboth 3,255,637 6/ 1966 Boyles 200/ 168 G UX sets of bridging contacts.

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PATENTEDncI 12 Ian 3, 12,793

sum 2 [IF 4 ELECTRICAL SWITCH COMPONENTS AND SWITCHES FORMED THEREBYBACKGROUND This invention is concerned with the electrical switch artand more particularly with components in snap action mechanisms and themechanisms formed thereby.

More specifically, this invention relates to a compact elegantcombination switchblade and contact means which is exceedingly useful insnap switch mechanisms, certain other novel components, and when all arecombined with other components, rugged precision snap switches areprovided. One primary use of the combination switchblade and contactmember is in a single-pole double-throw switch of the type often calleda two circuit switch. it differs from the ordinary single pole switchesin that it is provided with four terminals and a movable bridgingcontact mechanism is adapted to selectively contact either of two pairsof terminals to complete a circuit. This general type of switchmechanism is sometimes referred to as a butterfly mechanism, thebridging contact mechanism being analogous to the movable wings."

Butterfly type prior art snap switches of extremely limited scope wereproposed at least 40 years ago but apparently did not enjoy extensivecommercial success due at least in part to lack of any suggestion of anyof the necessary precisional qualities required by modern industry (seeUS. Pat. No. l,645,528). Prior art precision snap switches of thebutterfly type, as for example, the two circuit snap switch shown in myprior US. Pat. No. 2,840,657 offered a major improvement over theflexible blade type switches more commonly used prior to the inventionthereof. However, the instant switch, while having some similarity tothe "butterfly" action of each of the above patents, represents dramaticimprovement and sharply differentiates from each of the mechanisms ofthose patents as shall become apparent hereinafter.

The prior art mechanism shown in my US. Pat. No. 2,840,657 provides athird class levering system which is severely restricted in design in alongitudinal direction (between outboard edges of the butterflymechanism) because of the many elements to be disposed serially.Starting at the centerline of the butterfly actuator and movable contactmechanism of my previous patent, there are required: Stock on theactuator for carrying the precision pivot points, legs on the flatswitchblades of sufficient length to provide good action, stock for theattachment means in the bight of the U- shaped legs to couple thecompression and tension portions of the mechanism, and stock on the flatswitchblades to attachably mount the top and bottom contacts on the endof the flat switchblade.

In a truly small switch of my previously patented type, the top andbottom contacts take so much space at the end of the flat blade, thatthere is not sufi'tcient room for the mechanism (actuator, legs,attachment means, and tension spring). Stated in another way, thecontacts required by the electrical parameters so dominate the mechanismthat in a very real sense, it is the limiting factor. There are twodifferent facets to this lack of longitudinal room for the mechanism inmy previously patented switch, namely:

(1) lnsufficient length for necessary mechanism geometry to perform thefunction, and

(2) Insufficient space for adequately strong and long-lived tensionspring members.

It is the overcentering of the line of action of the tension springmember in butterfly-type mechanisms that provides a snap action to thecontacts. It is desirable to have the distance of movement of the lineof action of the spring be as large as possible in extremely smallmechanisms. In my previously patented mechanisms this overcenteringdistance is typically one-half of the contact throw or gap. The smallerthe switch the smaller the ratio of the overcentering movement tocontact gap. As my aforementioned patent mechanisms get smaller andsmaller, the small overcentering movement produces two practical evils,namely:

(1) Low decisiveness at the trip point, known as dead break, and

(2) Lack of simultaneity in operation of the two switchblades. Simplyput, this is poor snap action.

The earlier mechanisms, such as shown in U.S. Pat. No. 1,645,528, wereessentially concerned with single circuit mechanisms (on or off), arelacking in symmetry, have only a single contact surface on the bridgingmechanism, lack precision characteristics of pivot, have poor attachmenttechniques for the spring, etc. such that the teachings of this patenthave little relevance to modern compact precision snap switchconstruction.

SUMMARY The new switch mechanism described in detail hereinafter notonly overcomes the aforementioned problems, but additionally providesother advantages.

Two circuit snap switches of my new invention find wide use in aircraft,ships, and control usages in industry, and is particularly well adaptedfor usage where precision snap action push button switches are desiredfor panel boards, control sticks, pressure switches, or any hand ormachine operated use. The precision qualities of the below identifiedswitch qualifies it as a limit switch with unique size, rating, sealingand economy features.

With the foregoing in mind, it will be noted that there is provided acombination switchblade and contact means wherein the contact means isintegral with the switchblade-the member is one-piece unitarystamping-and due to the construction thereof forms a second classlevering system as distinct from a third class levering system to afforda far more effective powering of the snap mechanism.

The second class lever operation with the tension spring provides agreater leverage and a longer throw or moment on the contacts in my newmechanism. The length of the lever associated with the overcenteringforce compared to the length of the lever to the contact force isfavorable in my new mechanism. The ratio of the moments of these twoforces (overcentering force-contact force) is greater than unity in mynew mechanism whereas in my previous patent it was less than unity.

Thus this invention teaches a mechanism which is very effective inproducing contact force.

This same second class lever system provides advantages in that itafiords a configuration of mechanism such that the tension spring memberthrows the bridging mechanism overcenter with a significant increase inthrow over prior art capabilities. With this greatly increased throw" itis now possible to have good definite snap action in very smallmechanisms. There is sufficient movement in a butterfly mechanism sothat the first side (left for example) to start in motion helps theother (right side for example) overcenter with resultant goodsimultaneity and no double" clicking.

It is a further advantage of this invention to provide a second classlever system in a butterfly snap action mechanism which is economicalwithout sacrifice of high precision and compactness. Another advantageis the provision of a two circuit snap switch wherein physically smallcompact mechanisms may be provided through the elegant use of the spaceintermediate spaced contacts.

The new mechanism has a configuration providing a tension spring memberof greatly increased length which in turn provides increased leverageand better switching geometry, the increased length allowing for astronger spring which gives a truly remarkable force in even extremelysmall mechanisms. In one practical instance of a switch mechanism havinga butterfly wingsprea of less than one-half inch, there is produced ameasured contact force of grams. This increased force confers a goodsnap action feel and also gives a very low value of contact resistance.Testing has revealed consistent contact resistance capabilities below 4milliohms in the aforementioned small switches which are of theconstruction shown and described herein. l-Ieretofore, in similar sizeswitches, milliohms has been considered good. This major reduction ofthe contact resistance is significant in the problem of flicker inswitches, but with the high force produced by this new mechanism,contact flicker is now essentially eliminated and there is a 100 percentreliability on contact make.

This invention provides a levering system and construction features fora snap mechanism which affords low contact bounce, an extremely usefulfeature whenever solid state circuits are used. The levering mechanismalso provides a compact switch mechanism having extremely desirablecharacteristics of low flicker," and low contact resistance which aremaintained under extreme conditions of vibration, shock, andacceleration. Other useful advantages of the below-described switchconstruction are the economic aspects in that the parts are formed fromsimple stampings, the parts are easily to assemble, few parts arenecessary, and there is an exceedingly effective use of the small spaceavailable interiorly of the switch. Still further advantages are aswitch mechanism which is exceedingly reliable in that it obviates deadcentering in a mechanism where there is a positive snap action, which iswell adapted to handle electrical overloads, and where a mechanism isprovided which is mechanically and electrically of great strength.

More particular advantage of this invention are to provide a switchwherein the mechanical actuation of the movable switch parts canreliable withstand a quarter of a million mechanical cycles, to providea mechanism which has a trip point repeatability of greatdefinitiveness, to provide a mechanism which is sealed againstenvironment and flux and to provide a mechanism where the casing thereofis well adapted to a variety of mounting styles.

Another advantage of this invention is the provision of a sealed switchmechanism wherein the movable push button is sealed to the casing by alimp flexible boot of impermeable material using a rolling sleeveprinciple as distinct from a bellows mechanism, the rolling sleeveproviding a uniform negligibly low resistance to movement over a largetemperature range.

The snap action mechanism is also well adapted to reliably meetmid-porxion, and difficult military specification standards, forexample, military standards MIL-S-8805/3 and MS 25089, as well as UnitedStates Navy high shock tests, all of the above specification standardsincluding extraordinary ranges of vibrational, acceleration and shocktests in wet environments over an extreme temperature range.

An improved common terminal means which is easy to assembly and mountwhile affording an economical solder pot is another feature of theinvention. Prior art common terminals often have not been well adaptedto satisfactory mounting to normally encountered production variances inthe plastic case and subsequentially providing a solder pot afterinstallation. Herein there is taught a common terminal means' which ismounted in situ by deforming the sidewalls thereof in a manner toprovide a resilient strut attachment means to afiord good mountingcharacteristics over a wide variety of tolerances of case structures andsimultaneously providing openings in the sidewalls of the terminal toafford a good solder pot which allows escape of gas and othercontaminants. It will alsobe noted that the method of attaching a commonterminal means to afford the foregoing characteristics requires onlysimple tooling and economical reciprocation motion.

It is an advantage of this invention to provide a basic mechanism whichis well adapted for usage in a wide variety of switch types including alow travel type, a sequential type, two pole four circuit snap switchtype, and the like.

In the two pole four circuit snap switch mechanism there is a mechanismprovided which stores energy during the operation of the switch so as topositively insure simultaneous actuation operation or snap movement ofall of the moving contacts to thereby insure against improper switchoperation, the

means to so provide being simple and economic. More particularly, thetwo pole four circuit mechanism provides an energy storing means forstoring the initial energy of actuation so that when the switchmechanism resistance of one pair of movable contacts approaches zero,the stored energy in the energy storing means will aid in tripping andinsuring positive overcentering of the centering of the second pair ofmovable contacts to thereby assure simultaneity of action.

It should be noted that the switchblade contact member has an endportion which is deliberately cylindrical, whereby the end portionalways presents the same amount of contact gap, no matter what angle thelegs portion of the switchblade assumes during its action to thus affordgood are interrupting ability and ability to withstand dielectricbreakdown voltage of significant values. An improved method of attachingthe ends of the tension spring is provided in the new mechanism byforming a shear form strut structure in the cylindrical end of theformed blade which, in addition to the attachment function performs astrengthening strut action to maintain dimensional stability of thespaced contact surfaces.

The attachment strut means aforediscussed takes a minimum of space andis so arranged and proportioned that the spring attaches immediatelyadjacent to the end of the blade. The strut is deliberately formed witha radius which mates with the rounded cross section of the tensionspring to provide good wear characteristics through extreme cycling ofthe switch without a sawing effect.

Additional advantages of the present invention will be apparent from thefollowing descriptions when taken in connection with the accompanyingdrawings.

DRAWINGS FIG. 1 is a top perspective view of a single-pole, doublethrowswitch utilizing the aforediscussed snap action mechanism and commonterminal means, said view being approximately actual size of onecommercial embodiment;

FIG. 2 is a partial sectional view of the mechanism shown in FIG. 1;

FIG. 3 is a top view along lines 3-3 of FIG. 2;

FIG. 4 is a bottom view along lines 4-4 of FIG. 2 with the terminalextensions removed for clarity;

FIG. 5 is a greatly enlarged internal elevational view partially insection similar in many respects to FIG. 2, but rotated approximatelyand taken along lines 5-5 of FIG. 6;

FIG. 6 is a sectional view taken along lines 6-6 of FIG. 5;

FIG. 7 is a semidiagrammatic view of a force diagram indicating thegeometry of the combination switchblade contact mechanism shown in theforegoing figures;

FIG. 8 is a plan view of the switchblade contact structure in greatlyenlarged size, the dotted midportion, portion showing the configurationprior to formation of the curvilinear contact end structure thereon;

FIG. 9 is a side view of the structure shown in FIG. 8 subsequent to theformation of the contact structure;

FIG. 10 is an end view of the contact structure shown in FIG. 9 alonglines 10-40 of FIG. 9;

FIG. 11 is a partial elevation and sectional view of the mechanism shownin FIG. 2 with some of the parts removed and with the bottom commontenninal means being rotated 45 to give a clear indication of theformation of the common terminal means by the tool shown in FIG. 11A;

FIG. 11A indicates the tool which reciprocately moves to form theresilient strut attachment means on the common terminal meansimmediately thereabove in FIG. 11;

FIG. 12 is a bottom view of the button shown in FIGS. 2, 3 and 5 forsliding association with the bore in the casing means shown in FIG. 11;

FIG. 13 is a view along lines l3--l3 of FIG. 11 indicating the formationof the common terminal means, said common terminal means being rotatedapproximately 45 from that shown in FIG. 4 for pictorial reasons only;

FIG-13A is a side view of the tool shown in FIG. 11A;

FIG. 14 is a side elevational view of the upper terminal member alonglines 14-14 of FIG. 15 and also shown in FIG.

FIG. 15 is a plan view of the terminal member of FIG. 14;

FIG. 16 is an elevational view, partially in section of an alternateembodiment switch, namely a two pole four circuit switch using thegeneral snap switch mechanism shown in the preceding figures;

FIG. 16A is an isolated plan view of the energy storing rubber donutshaped member usable in mechanisms of the type shown in FIG. 16;

FIG. 17 is an elevational view partially in section of another alternateembodiment of switch mechanism that may be classified as a low travel"switch mechanism using the combination switchblade and contact means ofother mechanisms shown in the earlier figures;

FIG. 18 is a partial sectional view of the flexible, button sealingmechanism, on greatly enlarged scale, utilizing the rolling sleeveprinciple;

FIG. 18A is a partial sectional view similar to FIG. 18 showing therelationship of the parts in actuated position;

FIG. 18B is a perspective view of the sealing means shown in FIGS. 18and 18A;

FIG. 19 is a side view along lines 19--l9 of FIG. 16;

FIG. 20 is a partial sectional and elevational view of an altematemechanism which assures positive sequential switching;

FIG. 21 is a side elevational view along lines 21-21 of an alternateembodiment of a push-pull type snap switch mechanism shown in FIG. 22;and

FIG. 22 is a front elevational partial sectional view along lines 2222of FIG. 21 showing a push-pull mechanism using the snap mechanism ofpreceding figures.

Referring now with greater particularity to the drawings, andspecifically to FIGS. 1 through l4, 18, 18A and 18B, there is shown acompact precision two circuit snap switch mechanism which broadlycomprises a support means 12, movable actuator means 14, combinationswitchblade and contact means 16, terminal means 18 and sealing means20.

More particularly, the support means 12 comprises an inner dielectriccasing means 22 and an outer protective casing means 24. The innerdielectric casing means is preferably formed of a sturdy plastic such asBakelite and the like, which has good dielectric strength properties aswell as desired mechanical properties of structural strength. The outerprotective casing means 24 is preferably formed of metal such as forexample aluminum and has an enlarged collar 26 adjacent to the topthereof to provide a shoulder 27 for engagement with a suitable panel,control stick, or other mounting surface.

As can be observed in FIGS. 1, 2 and 5, the switch mechanism 10 has agenerally cylindrical shape and the other casing means 24 is generallybarrel shaped with sidewalls 28 depending from the collar portion 26 toencase the moving portions of the switch. The bottom of the outerprotective casing 24 terminates in an open end portion 30 and the innerdielectric casing means 22 is snugly telescopingly disposed therewithinas shall be discussed. On the sidewalls 28, adjacent the collar 26 andshoulder 27 are threads 32 for mounting washers and nuts (not shown) toin turn mount the switch in conventional manner.

The interior of the outer casing means 24 is formed with threeconcentric bores, namely, the upper smallest bore 34 which mounts theswitch actuator means 14, slightly larger counter bore 36 of relativelyshort axial height which contains the upper sealing means 20 and thelarge cylindrical bore 38 which forms the main portion of the switchhousing per se. A transverse shoulder 40 connects the bores 36 and 38and provide one surface for mounting the sealing means 20 as shall bedescribed.

The inner dielectric casing means 22 is shown in isolated view in FIG.11 and is also shown in assembled relation to the outer casing in thevarious sectional views of FIGS. 2, 5 and 6 and comprises a base portion42 having upwardly extending cylindrical outer sidewalls 44 which snuglyfit in bore 38 and terminate at an open top end portion 46. The baseportion 42 has a pair of oppositely disposed through aperture means 48aand 48b for receipt of upper terminals to be further described indetail. The apertures 48a and 48b are generally rectilinear in shape andare symmetrically disposed on opposite sides of the axis of the outercylindrical walls 44 and quite closely adjacent thereto for maximummechanical spacing of the terminal members to be inserted therewithin.Another pair of similarly rectilinearly formed lower terminal throughapertures 50a and 50b are shown in FIG. 4. (It should be noted that inFIG. 4 the apertures are shown with the upper and lower terminalsremoved therefrom for purposes of pictorial clarity.) Apertures 50a and50b are symmetrically oppositely disposed relative to the axis of thewalls 44 at maximum spacing to each other and to apertures 48a and 48b.It will be noted that each of the apertures 48a and 48b, 50a and 50bhave expanded mid portions 52a, 52b, 52c and 52d for purposeshereinafter described.

As can best be seen in FIG. 11, through upper terminal apertures 48a and48b become open slots in the side walls 44 of casing means 22 and eachrespectively have upper portions 540 and 54b which extend from baseportion 42 to the open end 46. The radially outwardly portion expandedmid portions 52c and 52d also become open slots 56a and 56b which arecoextensive with open slots 54a and 54b as shown.

The base portion 42 is also formed with a small central bore 58 and anenlarged counter bore 60 defining a shoulder 61 therebetween. Theoperative functions of the bores 58 and 60 and the shoulder 61 shall bedescribed during the description of the common terminal means.

As can best be perceived in FIG. 6, the walls 44 of the internal casingmeans are not of uniform thickness, the bore 62 forming the main housingbeing generally ellipsoidal in shape when viewed in cross section. Sincethe exterior walls 44 are cylindrical, the ellipsoidal bore 62 fonningthe interior wall of the casing means 22 have thinned downed portions640 and 64b on the major axis of the ellipsoidal interior bore andthickened portions 66a and 66b on the minor axis of the ellipsoidalbore. The thin portions 64a and 64b of the housing, on the major axis ofthe bore, provide maximum operating space for the combinationswitchblade and contact means 16. The thickened portions 66a and 66b ofthe sidewalls, on the minor axis of the bore, provide mechanicalstrength for mounting the upper terminal means in slots 54a and 54b thestrength in the stock for slots 54a and 54b also being needed in theiradditional functions as rotation preventing keyways and precision slidesfor the actuator means 14 as will become apparent. The base portion 42is formed with a transverse wall surface 68 which becomes the interiorbottom wall of the switch mechanism and an outer transverse wall 70.After assembly,

the wall 70 and the apertures therein are covered with a thin layer ofsealing material or potted" with suitable epoxy potting compound 198, toprovide a sealing of the bottom of the switch.

The actuator means 14 comprises a bottom member 72 formed of a moldeddielectric material (preferably Nylon, Delrin or the like) and anelongated metal member 74 in force transmitting relationship thereto.The actuator means also includes a pair of return springs 76 and 78 forreturning member 74 and button 72 to their at rest positions shown inFIGS. 2 and 5. The return springs also serve an electrical function aswill be described.

The button member 72 may be best perceived by a close examination ofFIGS. 2, 5 and 11 and essentially comprises an upper cylindricalexterior portion 80 having a top 82 which is adapted to be manuallyengaged, cylindrical depending sidewalls having a portion 80 exterior ofthe housing a portion 84 located interior of casing 24, and an enlargedbottom flange portion 86. A bottom surface 87 of the bottom member isformed with a rectilinear central aperture 88 for receipt of the member74. There is a C-shaped sink 90 for mold cooling purposes which may beformed in the bottom surface 87 of the button for effective molding ofthe button 72. The bottom flange 86 is preferably formed with a shapecomplimentary to the interior bore 62 of the dielectric internal casingmeans 22 and, as will be perceived by comparing FIGS. 11 and 6, theseshapes are substantially identical. The bottom flange 86 if formed witha pair of oppositely disposed rectilinear key lugs or wings 92a and 921:which are adapted to slide in open casing slots 54a and 54b of the innercasing means 22. It will be noted that the lugs 92a and 92b do not fitinto the extensions of the shallow enlarged mid portions, slots 56a and56b. Thus, a slight space is provided between the outer edges of thewings or lugs 92a and 92b and the radially outwardly walls of theenlarged mid portions 56a and 56b to afford free movement of air or gaswithin the interior of the sealed switch casing upon actuation of theswitch button to thereby prevent any compression or pistonlike actionduring actuation. The remaining curvilinear portions 94 of the flange 86closely mate with the sidewalls forming the bore 62 of the casing means22.

The metal actuating member 74 is generally rectangular in cross sectionand disposed along the vertical axis of the switch 10 with the longcross-sectional dimension thereof disposed on the minor axis of bore 62.The member 74 has an upper reduced width portion 96 having a top 97which engages the bottom of the central aperture 88 in the button 72.The actuator 74 has an enlarged mid portion 98 connected to upperportion 96 by a shoulder 104i, and a reduced width short bottom portion100 which fits within the inner and outer concentric springs 76 and 78as shown in FIGS. and 1 l. A central, ovalshaped, elongated, transverseaperture 102 is centrally formed in the midportion 98 and extends fromthe bottom portion 100 upwardly into the narrow upper portion 96. Twopairs of op posed V-shaped notch portions 106 are formed on oppositesides of the aperture 102 and on opposite faces of the mid portion 98 asmay be seen in FIGS. 5 and 11. The V-shaped notches 106 serve as pivotalpoints and as precision locations for the combination switchblade andcontact means 16. It will be noted that the shoulder 104 formed betweenthe mid portion 98 and the necked down portion 96 of member '74 islocated immediately adjacent to the notches 106, there being onlysufficient backup stock above the notches as necessary to preventdistortion of the notches for purposes hereinafter appearing. A lowertransverse shoulder 108 if formed on member 7% between bottom portion100 and midportion 98 and engages the return springs 76 and 78 whichbias member 74 and button 72 in an upwardly direction.

The metal actuator member 74 mounts the combination switchblade andcontact means 16 and initiates the snap action thereof to affordelectrical switching. The combination switchblade and contact means 16comprises a pair of identical members 109a and and each is preferablyformed in a unitary integral manner from relatively sturdy sheet stockin a stamping type of forming operation. The members are preferablyformed of distinctly major parts of silver and minor amounts of nickeland magnesium added for purposes of hardness, the preferred proportionsbeing 98 percent silver and the remaining 2 percent being nickel andmagnesium added for hardness, such material being available under thetrade name Consil of the Handy and Harmon Company in the U.S.A.

As shown in detached view FIGS. 8, 9 and 10, and in assembled view inFIGS. 2, 5 and 6, the combination switchblade and contact means 16individual members 109a and 10% each have a first end portion 110comprising a pair of spaced legs 112 and 114, a midportion 116 and acurvilinear second end portion 118. The legs 112 and 114 are spacedapart a dimension D greater than the diameter of a tension spring 120which passes therebetween as will be perceived in FIGS. 5 and 6. Thetension spring 120 is conventionally formed of stainless steel. Thecombination switchblade and contact means 16 is initially blanked out ofstrip stock and as shown in FIG. 8, the second end portion 118 isinitially flat as shown by dotted lines indicated by the number 122.

A combination strut and attachment means 124 is shear formed in thesecond end portion 118 as indicated by the dotted parallel lines in theflat end 122. As may be seen in FIG. 8, the shear form strut andattachment portion 126 is deformed from the plane of. portion 122 whileit is flat prior to the curling of the end to the curvilinearcylindrical shape 118 as shown. Strut attachment 124 is relatively shortand stubby and an integral part 126 of the contact means 16 centrallyformed in the end 118. As shown, it is formed with a reverse curveportion 131. Portion 131 mates with the end of coil spring 120 for a lowwear connection. The attachment strut means 124 has a width dimension atleast as great or greater than the cross sectional thickness of thematerial. For extra long life connection, the portion 131 may be formedin a saddle shaped configuration as shown most clearly in FIG. 9. Itwill be noted that the deformed portion 126 fonns a sturdy separatingstrut separating upper contact portion 128 and lower contact portion 130so as to resist any deformation and or flexure of the connecting portiontherebetween to maintain dimensional stability and integrity throughoutthe life of the mechanism. The lower contact surface 130 is located inthe same plane as the first portion and the mid portion 116, whilecontact surface 128 is offset from that plane.

As viewed in top view (see FIGS. 6 and 8), it will be noted that thesecond end portion 118, particularly at the portion 128 from which formsthe upper movable contact, is narrower in width than the outboard edgesof the spaced legs 112 and 114. This narrowed end portion 118 allows theentire combination switchblade and contact means 16 to pivot in notches106 around sharpened edges 132 and have the necessary mechanicalclearance to the thin portions 640 of the inner dielectric casing means22. Stated another way, maximum utilization of space along the majoraxis of the oval interior of the casing 22 is provided by necking downor narrowing of the width of the second portion 118 of the combinationcontact and switchblade member. The sharp edges 132 in notches 106provide precision pivot points.

As aforenoted, the strut means 124 is preferably formed with a reversecurve shape which extends toward said first end portion 110 as viewed inside view in FIG. 9. The center 131 of the strut reverse curve isadjacent the axis of the cylindrical end portion 1 18 so that the lineof action of spring and the point of attachment of spring 120 issubstantially in a plane which bisects the area intermediate the spacedcontact portions 128 and 130. It will also be noted that the strutattachment means 124 is located in a plane that bisects the areaintermediate the spaced legs 112 and 114 for symmetrical balancing offorces caused by tension spring 120.

Due to the relatively short length of strut means 124 (as viewed in sideview), the curvilinear contact portions and 128 are provided with asturdy strut action to maintain dimensional stability therebetween. Thismaintenance of dimensional stability is important in switchingmechanisms where fairly high current loads may be encountered. (When itis remembered that military standard testing referred to in the earlyportion of this specification requires that a switch of the sizeapproximately shown in FIG. 1 must maintain five overloads of 600 amps,the maintenance of dimensional stability and prevention of arcing uponactuation of the switch is of importance.)

Also of note is that the end portion 118 is deliberately of a generallycylindrical shape as viewed in side view. The axis of the cylindricalend portion 118 is in a plane parallel to the plane of the flat firstportion 110 and midportion 116. This is advantageous in tooling and informing of the part and provided electrical advantages as will beexplained hereinafter. The curvilinear strut means 124 is locatedoutwardly or away from pivotal sharpened edge 132 a greater dimensionthan the upper and lower contact portions 128 and 130 are spaced fromsaid pivotal edge. The force diagrams involved and the advantages ofthis configuration which provides a second class levering system will beset forth in more detail in the description of the operation of themechanism.

It will be noted that in the instant embodiment of switch, the tensionspring 120 passes through aperture 120 in member 74 so as to mount thepair of opposed combination switchblade and contact members 1090 and10911 in the opposing V- shaped notches 106. It will be further notedthat the individual combination switchblade and contact members 109a and10911 are rather stubby and ruggedly formed so as to be rigid andwithout flexure to any measurable degree.

The opposed members 1090 and forming the combination switchblade andcontact means 16 are adapted to have the contact portions thereon besnapped between opposed fixed contact portions on upper terminal members134 and lower terminal members 136. It will be noted that each of theoppositely disposed symmetrical upper terminal members 134 are identicalin configuration and they are respectively disposed in casing slots 54aand 54b and through apertures 50a, 50b of the casing means 22. The upperterminal members 134 are shown in detached relation in FIGS. 14 and andin assembled relation in FIGS. 1, 2, 5 and 6 with each having a mainportion 138 which terminates in outer exterior portion 142. The terminalmembers 136 are inserted in the through apertures 50a and 50b until stopmounting lugs 140 engage base casing surface 68 to correctly positionthe terminal members in the vertical position in the slots as shown.Adjacent the outer exterior ends of the terminal members 134 are throughtransverse apertures 144 which preferably are threaded for mountingthere circuitry. Since there are minute burrs that occur in a threadingoperation, the slots and apertures 50a, 50b, 54a, and 54!: are formedwith the aforementioned expanded mid portions 56a, 56b, 52c and 52d sothat any slight burrs formed in the threading operation on the terminalsdo not skive the plastic casing or break ofi so as to causecontaminating small particles interiorally of the switch duringassembly, further the expanded mid portions afford a good flow ofpotting compound for positive sealing of the terminals and the case 22.

The upper portions of the terminal members 134 are formed with anofi'set transverse portion 146 having a depending fixed contact 148thereon. The contact 148 is preferably made of electrical grade silverfor its good contact and conducting properties, the remaining portion ofmember 146 being composed of silver coated brass or the like (to formthe entire terminal member of the same composition as the combinationcontact and switchblade members 109a and 10% of FIGS. 8, 9 and 10 isuneconomic). It will be noted that the junction between upper transverseportion 146 and the depending portion 138 is necked down at 150 and, asmay be seen in FIG. 6, as a lesser cross-sectional dimension. Thisreduced dimension of transverse portion 146 affords necessary electricalclearance between upper portion 96 of actuation member 74 within therestricted requirements on space interiorly of the switch as may be bestperceived in FIG. 6. It will also be observed that shoulder 104 onactuation member 74 is located immediately adjacent to the notches 106so as to preserve vertical electrical clearance from the underside oftransverse portions 146 of the upper terminal means when movable switchblade members are in their at rest position in engagement with the lowerterminal members 136 and actuation member 74 is in its uppermostposition.

A pair of substantially identical lower terminal members 136 areassembled to provide the lower fixed contacts of the switch. Each of thelower terminal members 136 (see FIG. 5) are formed with a C-shaped upperportion having a midvertical portion 152, a lower shoulder transverseportion 154 on an upper transverse portion 156. As shown, transverseportion 156 is generally parallel with portion 154 and forms the lowerfixed contact portion for electrical contact engagement with contactportion 130 of the movable contact members 109a and 1091:. Lowershoulder 154 engages casing surface 68 to provide vertical stability inmounting the lower terminal means. An exterior depending portion 162 ofthe lower terminal means is essentially similar in length andconfiguration with portion 142 of the upper terminal members and alsoiii" formed with a through threaded aperture similar to threadedaperture 144. The opposed lower terminal members 136 are eachrespectively disposed in slots 52a and 52b as shown in FIG. 5 and fixedcontact portions 156 are vertically below and in direct opposition toupper depending contact portions 148 of the upper terminal members. Itwill be noted that each of the lower terminal members 136, as best shownin FIG. 5, are preferably formed of a bimetal, approximately one-thirdportion 162 being silver, the other two-thirds of the bimetal beingidentified with a numeral 164 preferably being of good electrical gradebrass which may be coated with a nontarnishing silver-type coating ifdesired. It will be observed that the fixed contact surface 156, isdeliberately composed of the one-third portion 162 of the bimetal of thelower terminal means which is comprised of silver.

The base portion 42 of the interior casing means 22 centrally mounts acommon terminal means 166 (see FIGS. 4, 5, 11, 11A, 13 and 13A). Thecommon terminal means 166 is generally cylindrical in configurationhaving a top surface 174, an enlarged head 170, and side walls 168depending from the enlarged heat 170. The head 170 and the side walls168 define a transverse shoulder 172 for engagement with coun terboreshoulder 61 in the casing base 42. A central bore 176 is formed in thecommon terminal means 166 from the end which is remote from the headedportion 170. The bore 176 does not extend all the way through member 166and thus the bottom and the inner walls thereof forms a centraldepression or "pot." A pair of combination attachment and resilientstrut means 178 are formed from the material of the sidewalls 168. Itwill be noted that the strut means 178 are symmetrically disposed onopposite sides of the axis of the bore 176 and while this is preferredfor simple tooling it is possible in some applications to have three orfour struts formed. However, when more than two struts are formed, thestruts, and the slots so formed would preferably be of lesser width topreserve the integrity and stability of the remaining upstandingportions 180 and 181. The movement of material from the side walls toform the attachment and strut means 178 performs the dual function of insitu mounting of the common tenninal means 166 to the casing 22 and alsothe movement of the material from the sidewalls forms the openings 183and 184 in an open sided solder pot." The pot" is defined by bore 176and the remaining upstanding curvilinear portions 180 and 181 of theside walls 168. As will be seen, opposed openings 183 and 184 areaxially aligned, relatively narrow, and of lesser length than bore 176.The openings 183 and 184 allow the escape of gas and contaminants fromthe pot during the later soldering of a lead wire to the common terminalmeans while the walls or extension 180 and 181 confine the solder to therelatively small space immediately adjacent to the terminal means toafford good electrical clearance to other parts of the switch.

As shown, the resilient strut attachment means 178 are integral deformedportions of the sidewalls 168 which have one end remaining attachedthereto after formation thereof. The strut means 178 are formed by thereciprocal movement of tool 186. (It will be perceived that the mountingoccurs after placement of a nondeformed common terminal means in bore 58of the internal casing means 22, fixing the head 170 against movementand then relatively moving the tool 186 and the common terminal means.)

The tool 186 shown in FIGS. 11A and 13A has a central locating portion188 which extends beyond the wall cutting and deforming portions 190 and192. As the tool 186 and terminal means 166 are moved toward each other,the engagement of sharp edges of portions 190 and 192 upon the end walls186 defined by bore 176 of the terminal member sidewalls 168 form theoppositely disposed strut means 178. The engagement of the end walls 186with portions 190 and 192 causes outward deformation of the sidewallswhich continue to move and assume the curvilinear shape shown. It willbe noted that each of the strut means 178 is formed so that it extendsradially outwardly away from the sidewalls at 194 and then back inwardlytoward the sidewalls as shown at 196. De-

pending on the length of stroke of tool 186, the strut in formationthereof, will spirally curl within itself while maintaining a mountingengagement to the mounting surface. Reflection will show that the lengthof slots 183 and 184 will always have a dimension, as measured from end186, which is greater than one-half of the distance form end 186 to themounting surface (such as switch casing bottom surface 70.) Thedimension which the strut extends outwardly from the sidewalls is afunction of the slope of surfaces 190 and reverse surface 191 and thecomplimentary surfaces 192 and 193 which determine the diameter of thecurl or spiral formed. Some resiliency is imparted to the constructionof the strut means 178 since it is not squashed flat against the surface70 and the free end of the strut member is predisposed to furthercurling. This slight resiliency is advantageous in preventing crackingor extreme stressing of the plastic cases to which it may be mounted,such as inner casing 22. As will be apparent, this structure of commonterminal means and the method of mounting same affords an accommodationto a wide variance in thickness between counterbore surface 61 and endsurface 70 of the base portion 42.

It will be noted that it is possible to have one size of common terminalmember usable for a variety of different switch constructions whereinthe mounting thickness varies from switch to switch. By merely having afixture which causes head portion 172 to be firmly supported, the commonterminal means is easily mounted in situs.

The configuration of the end of the forming tool 186 as aforenoted,causes the deformed material of the sidewalls to roll back withinitself, a particularly useful feature for small mechanisms whereelectrical clearance with other terminals is a problem. As will beobserved in FIG. 4, the resilient wing or strut means 178 for the commonterminal means 166 are so disposed and located on surface 70 so as tobisect the area intermediate the external extensions 142 and 158 of theupper and lower terminal members 134 and 136. The curling withinthemselves of the individual struts, as shown at 196, uses a minimumamount of space and maintenance of dielectric spacing to the otherterminals is obtained.

As seen in the drawings, the top 174 of the head portion 170 of thecommon terminal means 166 mechanically and electrically engages each ofsprings 76 and 78, each of said springs in turn mechanically andelectrically engage transverse shoulder 108 on actuator member 74. Sincemetal member 74 mounts the movable contact and switchblade means 16,electrical contact to the upper and lower contact terminals is providedthrough members 109a and The springs 76 and 78 have different hands toprevent interlocking between the two springs. The inner spring 76 ispreferably made of stainless steel to provide the mechanical strengthneeded for return action and mechanical resistance to shock andvibration. The outer spring 78 is preferably made of a silver, magnesiumand nickel alloy of the type aforediscussed relative to the movablecontact members 109a and 10%. Spring 78 may be formed of berylliumcopper in some applications. The primary function of the outer spring 78is electrical current carrying capacity and it is larger then the innerspring 76 not only in diameter of the coil but in diameter of wire size.

The upper end of the switch casing is sealed by a rubber boot 200 whichhas an initial shape somewhat similar to a hat as shown in FIG. 18B. Thehat-shaped boot 200 is sealingly trapped between shoulder 40 and the top46 of internal casing member 22, there being a washer 212 between, asshall be described.

More particularly, the hat shaped member 200 is formed with a laterallyextending flange portion 204, upstanding walls 210, a laterally inwardlyextending top portion 206 terminating in a central aperture 209. Thenonstretched diameter of aperture 209 is less than the outer diameter ofthe button 72. The margin of the boot immediately surrounding theaperture 210 is designated with the numeral 208. The hat shaped member200 is assembled to the button 72 by forcing the latter through theaperture 209. Circumferential Pressure thus created provides a sealbetween the boot member or sleeve member 200 and the button 72preventing ingress and egress of moisture and other contaminants. Afterinitial assembly, the end portion 209 and the margin 208 immediatelysurrounding same are placed at the inverted relationship to the buttonshown in FIGS. 5, 18 and 18A, this inversion being accomplished bymoving a small tube of approximately the same ID as the OD of the buttonwalls 84 into engagement with walls or margin 208 surrounding theaperture 209 of the boot causing the end portion to turn downwardlytowards the button flange 86 as shown. The subassembly thus created isthen assembled into the bores 36 and 44 of the outer casing as shown inFIGS. 5 and 18. Sealing compression on flange 204 is provided by the top46 of the inner casing 22 through the washer 212.

The sleeve or boot member is preferably made of silicone rubber materialhaving low structural integrity (almost limp). As shown in FIGS. 18 and18A, the movement of the button downwardly causes a rolling sleeveaction wherein portion 208 moves with the button walls 84 causing moreand more of portion 206 of the boot to move therewith. This rollingsleeve action requires very minute force and thus very low actuatingpressures to overcome the very low resistance involved. The siliconerubber maintains its limpness over large ambient temperature ranges andthis, together with the rolling sleeve principle affords constant andrepeatable trip point values.

When all of the aforenoted and described parts are placed in assembledposition as shown in FIGS. 2 and 5, the bottom portion of the casing ispreferably covered with an epoxy potting compound for sealing of thelower end of the switch. It is preferred that the electrical gradeepoxies of the thermo setting variety be used.

Attention is now invited to the free body force diagram shown in FIG. 7.In particular, attention is invited to the illustrated dimensions A, Band C. Dimension A is the distance between the end 132 and the contactsurface, said dimension being the same for both the lower contactsurface 130 and the upper contact surface 128 when either of saidcontact surface 130 and the upper contact surface 128 when either ofsaid contact surfaces are in contact with the lower and upper respectivefixed contacts 156 and 148. Dimension B is the dimension between the end132 of the point of attachment of the ends of spring to the attachmentstrut means 124. Dimension C is the amount of overcenter movement fromthe dead center position to the at rest position for the particulargeometry of parts shown. T is the line of action of the tension force ofspring 120, and Fv is the line of force of the actuation means 14. Fe isthe force on the contacts portions 128 and 130.

As aforestated, in prior art switches, particularly of the butterflytype, the prior art contact means generally so dominates the mechanismthat it has become a limiting factor in small models. This lack of roomfor efficient contact means in truly small prior art mechanisms givesrise to insufficient length for necessary mechanism geometry to performthe snap action function; and insufficient space for adequately strongand long lived tension spring members such as spring 120. The particulargeometry of the mechanism of the combination switchblade and contactmeans 16 shown in FIG. 7 provides a second class levering system sincedimension B is greater than dimension A. Stated another way, the contactforce Fe is subject to the mechanical advantage provided by the tensionspring 120 with force T working through the lever arm B. The contactforce Fc on both members 1090 and 109b is greater than the verticalforce component provided by spring 120.

It will be observed that the tension T provided by spring 12 provides avery effective powering of the snap mechanism ans also provides thecontact force when the parts are at rest. The tension provided by spring120 provides a long throw or moment to the movable members 1090 and1091). The ratio of B to A as shown in FIG. 7, compares the length ofthe lever arm B associated with the overcentering force, to the lengthof the lever arm A of the contact force and thus it is the ratio of the13 moments of these two forces. It will be noted that B is greater thanA and thus is greater than unity and as aforediscussed it is this ratioas applied to the tension T of spring 120 which produces contact force.

The ration B/A also has application to the distance that the tensionspring 120 throws the movable snap switch contact members over center onactuation of the switch. It provides a large throw so as to provide gooddefinite snap action. In this regard it will be noted that the distanceC is the distance the pivot point at 106 moves under force Fv so as toprovide overcentering In small mechanisms, it is desirable to have theovercentering movement C of the line of action of the tension force T beas large as possible since due to the large movement C, you get a gooddefinite snap action. Since the construction described provides goodsufficient movement in the vertical plane (the dimension C), thereby itassures no double clicking and good simultaneity. (Simultaneity in smallswitches is that aspect of assuring that when one side of the switchmechanism 109a for example goes over center, the other side will also goover center. There is a large movement differential in volved in thismechanism which is a function of dimension C and thereby dead centeringis eliminated.)

In the instant mechanism 10, due the greatly increased leverage, thespace to have a meaningful sized tension spring, and better switchgeometry above referred to, an amazing amount of contact force betweencontact surfaces such as 156 and 130 is possible for the at restpositions of the movable contact members 109a and 10%. This increasedcontact force confers good snap cation manual feed and also gives a verylow value of contact resistance. In many applications of manuallyactuated switches, it is important to the operator to know form atactile sense, that the switch has snapped overcenter. It will beappreciated that contact force initially resists the snapping overcenter upon actuation of the switch button 72, thus, the change fromhigh values in contact pressure during reversal is dramatic and confersthe requisite feel.

in small switches of the size shown in FIG. 1 (i.e., casing 24 having alength of approximately 0.90 inches and an OD of 0.562 inches),consistent contact resistance capabilities below 4 milliohms in switcheswhich meet the above referred to military specs have been obtained. Inprior devices milliohms resistance has been considered good, and thisreduction is a very significant 80 percent reduction over all knownprior art devices. This reduction of contact resistance to the lowvalues is significant in problems of flicker in switches. l-leretofore,a fairly high percentage of switches would flicker" when subjected tovibration, acceleration, etc., but with the high force produced by thismechanism, contact flicker is no longer a problem and there is greatreliability on contact make.

It has been previously referred to that as viewed from the side, the endportion 118 of the movable contact means 16 is a portion of a cylinder.This portion 118 thus presents, due to its configuration the same amountof contact gap to fixed contacts 148 and 156 no matter what angle thelegs 112 and 114 assume during the movement of member 74. With the usualoval faced contacts of the prior art devices, there is an angularbridging action which reduces the effective contact gap or electricalclearance which has disadvantage in both are interrupting ability and onthe dielectric breakdown voltage which may be sustained by themechanism.

Further, it has been found that the cylindrical contact surfaceapparently helps in obtaining reliability of contact closure in switchesof the type hereinabove described. It is thought that the curvilinearupper and lower contact surfaces 128 and 130 each make line contact withthe respective fiat fixed upper and lower contacts 148 and 156, at leastin theory. In practice, it is believed that due to extremely minutesurface irregularities, contact is made at two points on the line. Thisgives the effect of bifurcated contacts providing parallel current pathswith greatly increased probability of contact closure despite thepresence of extremely minute contamination. The radius of the contactsurface is much smaller for the cylinder on the end 118 than is typicalwith oval contacts used heretofore. Typically, for switches of the sizedescribed, the radius for the cylinder end 118 is on the order of 0.050inches compared to 0.125 inches for the conventional oval contact face.This sharper radius on the contact surfaces 128 and 130 increases unitcontact pressure and decreases the probability of a contaminant blockingcontact closure. This obtains because a particle of a given sizesay forexample 0.001 inches --is effective over only a small area where it canprovide intervention. The probability of closure is thus greatlyincreased by each of these mechanisms. Taking together the result isextremely good contact reliability.

The butterfly operation of the switch 10 is relatively simple andstraight forward. Movement downwardly of the actuator means button 72causes member 74 to move downwardly against the bias of springs 76 and78. The movable bridging contact and attachment means 16, beingrestrained by fixed lower contact surfaces 156, remain in contacttherewith until pivot points 106 pass the line of action (center line)of spring 120. The movable contact members then snap overcenter andupper contact surfaces 130 engage upper contacts 148 until such time asrelease of finger or other mechanical pressure on the top of button 72causes springs 76 and 78 to return the parts to the position shown inFIG. 5. As the member returns past the center line of spring 120, themovable switchblade members 1090 and 109k snap over center again inreverse.

From the foregoing description, it is apparent that a switch mechanismabove-described is spring return switch. That is to say that the springs76 and 78 return the parts to the at rest position shown in FIG. 5 sothat a circuit is completed between the two lower contacts (and alsothrough the common terminal means if so desired). This general type ofswitch is sometimes called a momentary switch. Also, it will be notedthat the upper pair of contacts 148 are bridged only when the button 72is held down.

If the springs 76 and 78 are omitted, a push-pull type of switch may beformed as is shown somewhat semidiagrammatically in FIGS. 21 and 22where similar parts are identified with similar numerals with theaddition of the prefix a and with new parts being identified without aprefix. The essential distinctions in this mechanism al0 are no returnsprings, the switch casing or support means al2 is rectilinear with theterminals (1134 and al36 shown coming out of the casing generallytransverse of line of actuation movement of the button and a slidingcontact means is provided for maintaining contact between the commonterminal means and the actuator n74. Movement of the button n72 to adownwardly position will cause members a109a and a109b to retainreversed position until button 072 is moved upwardly. As shown, thebutton 172 is formed with a narrowed waist 220 to facilitate the pull inreversing the switch. The common terminal means 0166 has a modified headstructure to accommodate to a sliding contact to the end a of membera74. More particularly, a cylindrical upstanding portion 222 isbifurcated to form upstand portions 224 and 226 having sliding contactsurfaces 228 and 230 which maintain constant contact with member a74.The switch 010 of the type shown in FIG. 22, when manually operated ineither direction, will remain actuated until a succeeding actuation inthe opposite direction. Also, the restoring force may be supplied by areturn button (not shown) of insulating material in place of commonterminal 11166. Also, a conducting spring of low force (not shown) maybe used to give good continuity during sliding of (1100 against 228 and230 if desired.

The particular embodiments of this invention heretofore and hereaftershown and described will be understood as being illustrative only.Various changes in structure will occur to those skilled in the art andare to be understood as forming a part of my invention insofar as theyfall within the spirit and scope of the claims. As has been generallyalluded to heretofore, the principles of this invention may be appliedequally well to a two pole four circuit switch. Such a switch M0 isshown in FIGS. 16 and 19 wherein similar parts are identified withsimilar reference numerals with the addition of the prefix b and whereonly new parts are identified with reference numbers without a prefix.It will be appreciated that FIG. 16 is semidiagrammatic representationand in principles of operation, there is a general similarity toaforediscussed switches al0 and 10. The construction shown in FIG. 16 isnot shown with a common terminal means, however, if it is so desired, acommon terminal means may be connected so as to be electricallyconnected to only the lower set of bridging contact means bl6b withoutmodification of other structure. Also, a restoring button (not shown)similar to a72 may be used instead of return springs [178 and b76 if apush-pull type is desired.

The actuator b7 4 is formed with an insulating section 240 whichprevents electrical interconnection between the upper bridging contactmeans bl6a and lower bridging contact means bl6b. Of particular interestin the construction shown in FIG. 16 is the unique energy storing means236 which stores energy during the early part of actuation and releasesthis energy to assure simultaneously of both sets of movable contactmeans b16a and b16b. More particularly, the energy storing meanscomprises a rubber donut shaped member 236 which is trapped in acounterbore 234 in the underside of the button means M2 by a washer 238said washer in turn engaging a shoulder bl04 on actuator member b74. Itwill be noted that there is clearance intermediate the top b97 of themetal actuator member M4 and the bottom of guide bore b88 in the buttonwhereby the force transmission form the button to the actuator member 74is only through compression of the energy storing rubber donut member236. As the donut 236 is further and further compressed, it reaches apoint where force from the button is transmitted to the actuator member74 moving same downwardly against the springs M6 and M8. As one of thetwo sets of bridging contact members has the line of action of thesprings bl come to dead center, the other spring member and bridgingcontact member is, due to the construction, also very close to the deadcenter position. As the first bridging contact means goes over center,the energy stored by the compression in the energy storing donut 236,aids in assuring that the second bridging contacts also reverse sincethe stored energy plus the sudden loss in resistance causes a suddendownward movement of the actuator member b74 in turn causing the othermember to quickly pass overcenter. This assures good simultaneity andimpossibility of double clicking. It is possible to have a suitablehelical coil spring substituted for donut 236.

A low travel switch mechanism 010 is shown in FIG. 17 in somewhatsemidiagrammatical form. Similar parts are identified with similarreference numbers with the addition of the prefix c and different partshave new reference numbers without the addition of a prefix.

The switch 010 essentially comprises a support means e12 actuator means(:14, combination contact and switchable means e16, for movement betweencontacts on terminal means 018, there being sealing means (:20 forkeeping contaminants from the interior of the casing formed by upper andlower portions 242 and 244, respectively. Casing portions 242 and 244mountingly support bracket means 246 having a base portion 252interconnecting spaced upstanding portions 248 and 250 and having anexternal common terminal 254. Portion 248 is formed with a mid aperture(not shown) and the top thereof on opposite sides of the mid aperture isformed with V-notches 0106 to mount the combination contact andswitchblade means 016. Portion 250 adjacent the top thereof is formedwith a shear form attachment means 256 in opposition to the attachmentmeans c124.

One end of spring c120 is attached to attachment 256 and the other tostrut attachment means c124. The bottom 258 of button (:72 is locatedrelative to the casing so as to impinge upon spring 0120 at 260 which isa point intermediate attachment part 256 and the pivot point 0106. Itwill be noted that a plane connecting point 256 and notches c106 isbelow a plane connecting points 256 and c124 and thus, the at restposition of the parts puts contact surface c128 in engagement with upperterminal means c134 fixed contact c148.

The switch mechanism e10 is different in certain respects from theearlier described switches and in a sense it is a onehalf butterflyswitch since only one wing" moves. it will be noted that switch 010 doesnot involve a movable metal actuator member having a pair of bridgingmembers pivoting thereon. Rather, the button member 072 is disposed sothat its end portion 258 engages portion 260 of the tension spring whichcauses the line of action of the spring 0120 to move past the planeconnecting pivot point 106a and attachment point 256. This causes themovable contact means cl6 to snap over center. One advantage of this lowtravel mechanism being that the aforedescribed second class lever isprovided for the movable contact means 016 which affords good stability,high contact pressure and precision actuation even though very smallmovements for actuation are involved. The movement differential for thebutton is very slight in mechanisms of the type shown in FIG. 17 and inthis sense it differs dramatically from the other figures. The amount ofactuation movement required, is a function of where the button end 258and engagement point 260 on spring 0120 is located. The further point260 is spaced from fixed pivot point 256 the greater the movementdifferential or more travel required by button e72 and of course theconverse obtains.

A sequential mechanism is shown in FlG. 20, said figure being in asemidiagrammatic form. The disposition of the parts is similar to thatshown in switches 10 and al0, and similar parts will be identified withthe same reference numerals using the prefix d. The essential differencebetween the mechanisms shown is that the upper and lower terminal meansare in offset relationship in the vertical plane. Note that terminal 266and contact 267 thereon are closer to lower tenninal 11136 as comparedto upper terminal dl34. This method of construction insures thatswitching occurs between circuits involved with the common terminalmeans dl66 and the movable contact on member 109a and fixed uppercontact 216 on the right side of FIG. 20, prior to switching occurringon the left side, i.e., with movable member dl09b making contact withthe fixed contact on terminal 270. Also, terminal dl36A (on the left)may be disposed lower than 11136 (on the right) so as to accentuate thetime delay between halves of the butterfly. Consistent sequencing times(depending on spacing) of 0.0005 to 0.002 seconds have been obtained.Thus, positive sequentially is obtained without denegrating the otheradvantages of the aforedescribed switches.

It has also been found that the combination contact and switchable meansshown in all of the embodiments may be formed from a bimetal composed ofa silver layer and a brass or phosphor bronze layer, although it ispreferred that care should be exercised to see that the contact portionssuch as 128 and 130 are of the silver portion of the bimetal.

I claim:

1. A unitary combination switchblade and contact means for compact snapswitch mechanisms comprising a member characterized as being a. ofone-piece and being formed solely from a single piece of material,

b. being electrically conductive,

c. formed with first and second spaced end portions interconnected by amid-portion,

d. said first end portion being characterized as i. having spaced legportions, ii. each said spaced leg portion having a low friction pivotaledge portion,

e. said second end portion being formed in a predetermined shape i.generally curvilinear as viewed in a direction transverse to a planeincluding a portion of said first end portion and said second endportion,

ii. said predetermined shape on said second end portion having upper andlower curvilinear contact portions located in spaced relation to eachother on said curvilinear shape and spaced from each other,

iii. said predetermined shape second end portion having an attachmentmeans portion formed from said curvilinear shape in alignment with saidplane including a portion of said first end portion and said second endportion, said plane extending between said upper and lower spacedcontact portions,

f. said attachment means portion being spaced from said edge portions adistance at least as great as each of said upper and lower curvilinearcontact means portions are spaced form said edge portions, whereby saidcontact means when pivoted about said edge portions by a biasing forceassociated with said attachment means and extending intermediate saidspaced leg portions and along said plane provides a second class leverfor pivotal movement around said edge portions.

2. The switchblade and contact means set forth in claim 1 composed ofdistinctly major portions of silver with minor portions of magnesium andnickel added for hardness wherein said first end portion and saidmidportion are located in a plane which angularly intersects a secondplane interconnecting said attachment means and said edge portion.

3. The switchblade and contact means set forth in claim 1 wherein saidcurvilinear second end portion is of generally cylindrical shape toprovide contact portions on the periphery thereof, the axis of saidcylindrical shape being in a plane generally parallel to a planeconnecting said first end portion and midportion, said attachment meansbeing a deformed portion of said cylindrical shape and being disposedgenerally transversally to said axis of said cylindrical shape.

4. The switchblade contact means of claim 3 wherein said member isstampingly formed from flat strip stock to provide a flat first andmidportion, said second portion being curved back toward saidmidportion, said deformed portion of said cylindrical shape forming saidattachment means also providing a strut action to maintain dimensionalstability between said spaced contact portions.

5. The switchblade contact means of claim 4 wherein said deformedportion of said cylindrical-shaped second end portion forming saidattachment means and providing said strut action is furthercharacterized as being:

a, located in a plane that substantially bisects the area intermediatesaid spaced leg portions, and

b. is of a curvilinear shape reversely curved from the cylindrical shapeof said second end portion and toward said first end portion, wherebythe pivotal attachment of an end of a biasing coil spring to saidattachment means will withstand a great number of mechanical actuationsof said switchblade with precision and without damage to the spring orthe attachment means.

6. A compact switch mechanism comprising support means, actuator meansmovable mounted relative to said support means for movement in a firstplane from a first position to a second position, spring means, andcombination switchblade and contact means pivotally mounted generallytransversally of said first plane for movement between A and Bpositions, said combination switchblade and contact means comprising acombination switchblade and contact member characterized a. a unitaryone-piece formed metal member having first and second spaced endportions connected by a midportion,

b. said first end portion comprising spaced leg means having means foraffording pivotal movement relative to said support means,

c. said spring means being a tension coil spring of a diameter less thanthe space between said spaced leg means extending between said space legmeans,

d. said second end portion comprising,

i. curvilinear spaced upper and lower contact portions,

and

ii. attachment means for said spring means, said attachment means beinglocated in a plane which extends form said means affording pivotalmovement relative to said support means and an area intermediate saidupper and lower spaced contact portions, said attachment means beinglocated outwardly of said means affording pivotal movement relative tosaid support means a distance greater than the distance between saidmeans affording pivotal movement relative to said support means and saidspaced contact portions, said attachment means affording a pivotalconnection to said spring means, whereby movement of said actuator meansin said first plane from said first to said second position causes saidcombination switchblade and contact means to pivotally move from said Aposition to said B position with a snap action, to provide low bounce ofsaid curvilinear contact portions upon attainment of said B position,and to provide a tendency of maintenance of said curvilinear contactportions in said B position with high vibrational, shock, andacceleration stability until said actuator means returns to said firstposition.

7. The compact snap switch mechanism of claim 6 wherein said supportmeans comprises a generally cylindrical shaped casing means having acentral actuator means receiving bore, said actuator means comprises anelongated metal member movable along the axis of the bore of saidcylindrical casing means, and button means, said button means having anexterior portion and an interior portion located within said bore ofsaid casing means, said button means being in rotation preventingrelationship with said bore in said casing and being in forcetransmitting, rotation preventing, relationship to said elongated metalmember, said elongated metal member having notch means and a throughaperture located intermediate the ends thereof, bias spring meansassociated with the end of said actuator means opposite from said buttonmeans for returning said actuator means from its second to its firstposition, upper and lower terminal means respectively having fixedcontact portions located adjacent to said B and A positions of saidcombination switchblade and contact means, said terminal means havingexterior portions extending beyond said casing means for connection toelectrical circuitry, whereby movement of said button means causes saidactuator member to move said combination switchblade and contact memberfrom engagement with lower terminal contact portion to engagement withsaid upper terminal member contact portion.

8. The mechanism set forth in claim 7 wherein said cylindrical castingmeans comprises an inner dielectric casing member and an outerprotective member, said inner casing member having generally cylindricalouter sidewalls and a closed end of said inner casing member having fourequally spaced through apertures located closely adjacent the plane ofsaid sidewall and a central through internally counter-bored aperture, apair of each of said upper and lower terminal members being disposed insaid four spaced apertures, electrically conductive common terminalmeans disposed in said central counterbored aperture, said commonterminal means having a closed, enlarged, head portion engaging themargin surrounding said counter bore and an exterior end portion, saidexterior end portion having bore means and resilient attachment strutmeans deformed outwardly from said exterior end portion, said attachmentstrut means being disposed in a plane substantially bisecting the areabetween the exterior portions of said upper and lower terminal meansdisposed in said four spaced apertures, said coil spring biasing meanshaving first and second ends, said first end being disposed in biasingforce transmitting and in electrical current transmitting engagementwith said closed head portion of said common terminal means and saidsecond end being disposed in force transmitting and electrical currenttransmitting engagement with said elongated metal actuating member, saidcoil spring biasing means comprising inner and outer concentric springsof similar length and different diameters, said inner and outer springseach having a difierent hand which prevents interlocking along the innersurface of the outer spring and the outer surface 'of the inner spring,whereby an electrical circuit may be switched from said common terminalmeans and said pair of lower terminals to said pair of upper terminalsthrough said biasing coil spring means, elongated metal actuator andcombination switchblade and contact means.

9. The switch mechanism of claim 7 wherein said casing means is formedwith an internal shoulder means adjacent said actuator means receivingbore, and low force rolling sleeve sealing means is disposedintermediate said casing means and said button means, said rollingsleeve sealing means comprising a flexible hat shaped member having acylindrical sidewall portion, an axially outwardly radially enlargedmargin adjacent the bottom of the sidewall portion sealingly, fixeddisposed adjacent to said casing means internal shoulder means, and atop portion being centrally apertured and extending initially toward theaxis of the sidewalls, said sidewalls being substantially uniform,flexible and sealingly connecting said top portion and said enlargedmargin, the margin surrounding said central aperture in said top portionbeing radially stretched and resiliently sealingly engaging said buttonmeans for movement therewith, said top portion moving toward saidenlarged margin with actuation of said button causing said thin flexiblesidewalls to rollingly fold within themselves at a uniform constant lowresistance while maintaining a seal between said casing means and saidbutton.

10. The mechanism set forth in claim 7 wherein said cylindrically shapedcasing means is formed of dielectric material and said central bore isgenerally ellipsoidal in cross section having a major and minor axis,said casing bore having axially aligned oppositely disposed slot meansformed in the margins of said casing means bore, said slot means beinglocated on the minor axis of said ellipsoidal casing bore, said upperterminal means for said mechanism comprising an elongated portion and anangularly offset portion having a fixed contact portion, said elongatedportion of said terminal means being disposed in said slot means withthe fixed contact portion being disposed on said major axis of saidellipsoidal casing bore, said button means of said mechanism having aradially enlarged margin portion with a shape complimentary to the shapeof said casing bore means, said enlarged margin portion being formedwith radially extending portions slidably fitting into said slot means,whereby said slot means serves as a keyway preventing rotation of saidbutton and said actuator means and mounts said upper tenninal means.

11. The mechanism set forth in claim 8 wherein said four equal spacedterminal receiving through apertures in said casing means are eachgenerally of a cross-sectional shape complimentary to the shape of theindividual said upper and lower terminal means, each of said throughapertures having oppositely disposed enlarged midportions, at least oneindividual terminal member of said upper and lower terminal membershaving a transverse threaded bore, said threaded bore of said terminalmember being aligned with said casing aperture enlarged midportion,whereby any burrs on said terminal members associated with or formed inthe threading of said threaded bores may pass freely through saidenlarged midportions without skiving of the margins of said dielectriccasing material, the said lower terminal means of said mechanism beingdisposed in an oppositely disposed pair of said through apertures, eachof said lower contact members having a fixed contact portion forelectrical contact with said combination switchblade and contact means,said lower terminal means being generally bimetallic first and secondmembers throughout the length thereof, said first member beingsubstantially one-third of the lower terminal means, an extremely goodelectrical conductor, and forming the fixed contact portion of the lowerterminal means.

12. The mechanism set forth in claim 6 which assures sequentialswitching wherein a pair of combination switchblade and contact meansare disposed in pivotally mounted opposed relation on said actuatormeans for simultaneous movement between said A and B positions, saidmechanism having a pair of upper terminal means, a common terminal meanselectrically connected to said actuator means, and a pair of lowerterminal means, each of said lower terminal means having a fixed contactportion located generally transverse to said actuator means and adjacentsaid A position of said combination switchblade and contact means, saidupper terminal means having fixed contact portions in staggeredtransverse relationship vertically above individual contact portions ofsaid lower terminal means, on of said upper terminal means fixed contactportions being disposed closer to said lower terminal means fixedcontact portions than the other of said upper fixed contact portions,whereby movement of said actuator means from its first to its secondposition causes one of said pair of combination switchblade and contactmeans to make mechanical and electrical contact with said one fixedcontact portion of said upper terminal means before the other of saidpair of combination switchblade and contact means makes mechanical andelectrical contact with said other fixed contact portion of said upperterminal means whereby a sequential switching action is assured.

13. The switch mechanism set forth in claim 6 characterized as a lowtravel mechanism wherein said tension coil spring has first and secondspaced ends, said actuator means comprises button means having anexterior portion and a spring means engaging portion, said spring meansengaging portion engaging said tension coil spring at a point along thelength thereof intermediate said spaced first and second ends, saidsupport means comprises bracket means having first and second spacedupstanding portions and a terminal portion, said first portion beingformed with through aperture means and notch means adjacent saidaperture means, said aperture means receiving said tension coil springand said notch means pivotally receiving said spaced leg means of saidcombination switchblade and contact member, said second upstandingportion being formed with a bracket spring attachment pivot point meansfor pivotal connecting receipt of said second end of said tension coilspring, said first end of said tension coil spring being attached tosaid attachment strut means of said combination switchblade and contactmember for movement with and for pivotal movement to said combinationswitchable and contact member, whereby deformation of said tension coilspring by said spring means engaging portion of said actuator meanscauses snap action movement of said combination switchblade and contactmeans.

14. The switch mechanism set forth in claim 13 wherein said tension coilspring is the sole biasing force in biasing said combination switchbladecontact means to said A position, exterior pressure on said exteriorportion of said button means causes deformation of said tension coilspring which in turn causes movement of said combination switchblade andcontact means from said A to said B position and release of pressure onsaid exterior portion of said button means causes said combinationswitchblade and contact member to return to said A position solely underthe bias of said tension coil spring.

15. The switch mechanism set forth in claim 14 wherein the amount ofrequired travel of said button means necessary to cause said combinationswitchblade and contact member to move from said A position to said Bposition is a function of the location of the point of engagement ofsaid spring engagement means portion of said button means upon saidtension coil spring means along the length thereof, the closer the saidpoint of engagement is located to said second end of said tension coilspring the greater the required travel of said button means necessary tocause movement of said combination switchblade and contact member fromsaid A position to said B position.

16. The switch mechanism set forth in claim 6 characterized as apush-pull mechanism wherein said actuator means when placed in said Aposition remains in said A position and when placed in said B positiontends to remain in said B position.

17. in a compact snap switch mechanism having support means, actuatormeans movably mounted relative to said support means for movement from afirst position to a second position, means for moving said actuatormeans relative to said support means, and meats to return said actuatormeans from said second position to its first position, the improvementscomprising a pair of discrete combination switchblade and contact meanspivotally mounted on opposite sides of said actuator means for movementbetween A and B positions, said combination switchblade and contactmeans extending generally transversally of said actuator means, andspring means connecting said combination switchblade and contact means,each of said combination switchblade and contact means beingcharacterized as being:

a. unitary one-piece formed metal members having first and second spacedend portions connected by a midportion,

b. said first end portion comprising spaced leg means having means forpivotally engaging said actuator means, said spring means extendingbetween said spaced leg means,

c. said second end portion comprising,

i. a pair of curvilinear spaced contact portions, one of said spacedcontact portions being located in the plane of said first end and midportions, the other of said spaced contact portions being offset fromthe plane of said first end and mid portions, and

attachment means for said spring means, said attachment means beinglocated in a plane which extends from said means for pivotally engagingsaid actuator and an area intermediate said spaced contact portions,said attachment means being located outwardly of said actuator means adistance at least as great as the distance between said actuator meansand said spaced contact portions, said attachment means affording apivotal connection to said spring means, whereby movement of saidactuator means from said first to said second position causes each ofsaid combination switchblade and contact means to move from said Aposition to said B position with a snap action and low bounce of saidcurvilinear contact portions and upon attainment of said B position, totend to maintain said curvilinear contact portions in said B positionwith high vibrational, shock, and acceleration stability until saidactuator means returns to said first position.

18. The switch mechanism set forth in claim 6 characterized as a twopole four circuit mechanism wherein said actuator means comprises anelongated member having a pair of sets of vertically spaced notch meansand a pair of through apertures respectively located adjacent to each ofsaid sets of notch means intermediate the ends of said member saidelongated metal member being further characterized as having aninsulating portion intermediate said spaced sets of notch means andthrough apertures to prevent transmission of electrical current betweenspaced portions of said elongated metal member, said elongated metalmember having a first shoulder means adjacent the top thereof and asecond shoulder means adjacent the bottom thereof, two pairs ofcombination switchblade and contact means, each respective pair havingspaced leg means located in one set of said notch means, bias springmeans associated with said second shoulder means for biasing saidactuator means towards its first position and each of said pairs ofcombination switchblade and contact means toward said A position.

19. The switch mechanism as set forth in claim 18 wherein said actuatormeans includes energy storing means located intermediate said firstshoulder of said elongated member and said button means, said energystoring means comprising a resilient compressible member proportionedand located in the line of force transmission of actuation energypressure on the button means for snap actuation of the combinationcontact and switchblade member, said energy storing means absorbing andstoring part of the energy pressure of actuation for later release, saidenergy storing means releasing the stored energy when one of said pairsof combination switchblade and contact members moves from said A to saidB position, the release of the stored energy assuring that the other ofsaid pairs of combination switchblade and contact means moves from saidA to said B position to thereby assure simultaneity of actuation of bothparrs of combination switchblade and contact means.

20. In a compact butterfly snap switch mechanism having support means,actuator means movably mounted relative to said support means formovement from a first position to a second position, button means formoving said actuator means relative to said support means, return biasmeans having a bias force of a predetermined magnitude to return saidactuator means from said second position to its first position, saidactuator means comprising an elongated member formed with a pair of setsof vertically spaced notch means and a pair of through apertures locatedadjacent to each of said sets of notch means, said elongated memberbeing formed of metal and with an insulating portion intermediate saidspaced sets of notch means to prevent transmission of electrical currentbetween spaced portions thereof, two vertically spaced pairs ofswitchblade means pivotally mounted on opposite sides of said actuatormeans for movement between A and B positions, said switchblade meansextending generally transversally of said actuator means, first andsecond spring means respectively extending through said aperture meansand respectively connecting said individual pairs of switchblade meansin said notch means on said elongated member, and energy storing meanslocated in the line of force transmission of actuation energy pressureon the button means for snap actuation of the switchblade means, saidenergy storing means being a resilient compressible rubber doughnutshaped member having a compressed and an uncompressed state, the forcerequired to compress said energy storing member from said uncompressedto said compressed state being less than said predetermined bias forceof said means to return said actuator means from said second position tosaid first position, said energy storing means absorbing and storingpart of the energy pressure of actuation for later release, said energystoring means releasing the stored energy when one of said pairs ofswitchblade means moves from said A to said B positions during movementof said actuator means from said first to said second position, therelease of the stored energy assuring that the other of said pairs ofswitchblade means moves from said A to said B position to thereby assuresimultaneity of actuation of both pairs of switchblade means.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,612 793 Dated October 12 1971 Inventofls) John O. Roeser It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

In column 3, line 42 change "mid-porxion," to -extreme--.

In column 9, line 27 change "there" to -other-.

In column 10, line 21 change "heat" to --head.

In column 11, line 6 change "form" to -from-.

In column 12, line 67 change "ans" to -and-.

In column 13, line 29 change "cation" to -action and change "feed" to-feel; in line 32 change "form" to -from-.

In column 16, line 42 change "sequentially" to -sequentiality.

In claim 8, column 18, line 49 before "closed" insert --closed bottomend at an end remote from said button means, said-.

In claim 9, column 19, line 13 change "fixed" to -fixedly. Signed andsealed this 9th day of May 1972.

(SEAL) Attest:

EDWARD M.FLE'ICHER,JR. ROBERT GOI'ISCHALK Attesting Officer Commissionerof Patents

1. A unitary combination switchblade and contact means for compact snapswitch mechanisms comprising a member characterized as being a. ofone-piece and being formed solely from a single piece of material, b.being electrically conductive, c. formed with first and second spacedend portions interconnected by a mid-portion, d. said first end portionbeing characterized as i. having spaced leg portions, ii. each saidspaced leg portion having a low friction pivotal edge portion, e. saidsecond end portion being formed in a predetermined shape i. generallycurvilinear as viewed in a direction transverse to a plane including aportion of said first end portion and said second end portion, ii. saidpredetermined shape on said second end portion having upper and lowercurvilinear contact portions located in spaced relation to each other onsaid curvilinear shape and spaced from each other, iii. saidpredetermined shape second end portion having an attachment meansportion formed from said curvilinear shape in alignment with said planeincluding a portion of said first end portion and said second endportion, said plane extending between said upper and lower spacedcontact portions, f. said attachment means portion being spaced fromsaid edge portions a distance at least as great as each of said upperand lower curvilinear contact means portions are spaced form said edgeportions, whereby said contact means when pivoted about said edgeportions by a biasing force associated with said attachment means andextending intermediate said spaced leg portions and along said planeprovides a second class lever for pivotal movement around said edgeportions.
 2. The switchblade and contact means set forth in claim 1composed of distinctly major portions of silver with minor portions ofmagnesium and nickel added for hardness wherein said first end portionand said midportion are located in a planE which angularly intersects asecond plane interconnecting said attachment means and said edgeportion.
 3. The switchblade and contact means set forth in claim 1wherein said curvilinear second end portion is of generally cylindricalshape to provide contact portions on the periphery thereof, the axis ofsaid cylindrical shape being in a plane generally parallel to a planeconnecting said first end portion and midportion, said attachment meansbeing a deformed portion of said cylindrical shape and being disposedgenerally transversally to said axis of said cylindrical shape.
 4. Theswitchblade contact means of claim 3 wherein said member is stampinglyformed from flat strip stock to provide a flat first and midportion,said second portion being curved back toward said midportion, saiddeformed portion of said cylindrical shape forming said attachment meansalso providing a strut action to maintain dimensional stability betweensaid spaced contact portions.
 5. The switchblade contact means of claim4 wherein said deformed portion of said cylindrical-shaped second endportion forming said attachment means and providing said strut action isfurther characterized as being: a. located in a plane that substantiallybisects the area intermediate said spaced leg portions, and b. is of acurvilinear shape reversely curved from the cylindrical shape of saidsecond end portion and toward said first end portion, whereby thepivotal attachment of an end of a biasing coil spring to said attachmentmeans will withstand a great number of mechanical actuations of saidswitchblade with precision and without damage to the spring or theattachment means.
 6. A compact switch mechanism comprising supportmeans, actuator means movable mounted relative to said support means formovement in a first plane from a first position to a second position,spring means, and combination switchblade and contact means pivotallymounted generally transversally of said first plane for movement betweenA and B positions, said combination switchblade and contact meanscomprising a combination switchblade and contact member characterizedas: a. a unitary one-piece formed metal member having first and secondspaced end portions connected by a midportion, b. said first end portioncomprising spaced leg means having means for affording pivotal movementrelative to said support means, c. said spring means being a tensioncoil spring of a diameter less than the space between said spaced legmeans extending between said space leg means, d. said second end portioncomprising, i. curvilinear spaced upper and lower contact portions, andii. attachment means for said spring means, said attachment means beinglocated in a plane which extends form said means affording pivotalmovement relative to said support means and an area intermediate saidupper and lower spaced contact portions, said attachment means beinglocated outwardly of said means affording pivotal movement relative tosaid support means a distance greater than the distance between saidmeans affording pivotal movement relative to said support means and saidspaced contact portions, said attachment means affording a pivotalconnection to said spring means, whereby movement of said actuator meansin said first plane from said first to said second position causes saidcombination switchblade and contact means to pivotally move from said Aposition to said B position with a snap action, to provide low bounce ofsaid curvilinear contact portions upon attainment of said B position,and to provide a tendency of maintenance of said curvilinear contactportions in said B position with high vibrational, shock, andacceleration stability until said actuator means returns to said firstposition.
 7. The compact snap switch mechanism of claim 6 wherein saidsupport means comprises a generally cylindrical shaped casing meanshaving a central actuator means receiving bore, said actuator meanscomprises an Elongated metal member movable along the axis of the boreof said cylindrical casing means, and button means, said button meanshaving an exterior portion and an interior portion located within saidbore of said casing means, said button means being in rotationpreventing relationship with said bore in said casing and being in forcetransmitting, rotation preventing, relationship to said elongated metalmember, said elongated metal member having notch means and a throughaperture located intermediate the ends thereof, bias spring meansassociated with the end of said actuator means opposite from said buttonmeans for returning said actuator means from its second to its firstposition, upper and lower terminal means respectively having fixedcontact portions located adjacent to said B and A positions of saidcombination switchblade and contact means, said terminal means havingexterior portions extending beyond said casing means for connection toelectrical circuitry, whereby movement of said button means causes saidactuator member to move said combination switchblade and contact memberfrom engagement with lower terminal contact portion to engagement withsaid upper terminal member contact portion.
 8. The mechanism set forthin claim 7 wherein said cylindrical casting means comprises an innerdielectric casing member and an outer protective member, said innercasing member having generally cylindrical outer sidewalls and a closedend of said inner casing member having four equally spaced throughapertures located closely adjacent the plane of said sidewall and acentral through internally counter-bored aperture, a pair of each ofsaid upper and lower terminal members being disposed in said four spacedapertures, electrically conductive common terminal means disposed insaid central counterbored aperture, said common terminal means having aclosed, enlarged, head portion engaging the margin surrounding saidcounter bore and an exterior end portion, said exterior end portionhaving bore means and resilient attachment strut means deformedoutwardly from said exterior end portion, said attachment strut meansbeing disposed in a plane substantially bisecting the area between theexterior portions of said upper and lower terminal means disposed insaid four spaced apertures, said coil spring biasing means having firstand second ends, said first end being disposed in biasing forcetransmitting and in electrical current transmitting engagement with saidclosed head portion of said common terminal means and said second endbeing disposed in force transmitting and electrical current transmittingengagement with said elongated metal actuating member, said coil springbiasing means comprising inner and outer concentric springs of similarlength and different diameters, said inner and outer springs each havinga different hand which prevents interlocking along the inner surface ofthe outer spring and the outer surface of the inner spring, whereby anelectrical circuit may be switched from said common terminal means andsaid pair of lower terminals to said pair of upper terminals throughsaid biasing coil spring means, elongated metal actuator and combinationswitchblade and contact means.
 9. The switch mechanism of claim 7wherein said casing means is formed with an internal shoulder meansadjacent said actuator means receiving bore, and low force rollingsleeve sealing means is disposed intermediate said casing means and saidbutton means, said rolling sleeve sealing means comprising a flexiblehat shaped member having a cylindrical sidewall portion, an axiallyoutwardly radially enlarged margin adjacent the bottom of the sidewallportion sealingly, fixed disposed adjacent to said casing means internalshoulder means, and a top portion being centrally apertured andextending initially toward the axis of the sidewalls, said sidewallsbeing substantially uniform, flexible and sealingly connecting said topportion and said enlarged margin, the margin surrounding said centralaperture in said top portion being radially stretched and resilientlysealingly engaging said button means for movement therewith, said topportion moving toward said enlarged margin with actuation of said buttoncausing said thin flexible sidewalls to rollingly fold within themselvesat a uniform constant low resistance while maintaining a seal betweensaid casing means and said button.
 10. The mechanism set forth in claim7 wherein said cylindrically shaped casing means is formed of dielectricmaterial and said central bore is generally ellipsoidal in cross sectionhaving a major and minor axis, said casing bore having axially alignedoppositely disposed slot means formed in the margins of said casingmeans bore, said slot means being located on the minor axis of saidellipsoidal casing bore, said upper terminal means for said mechanismcomprising an elongated portion and an angularly offset portion having afixed contact portion, said elongated portion of said terminal meansbeing disposed in said slot means with the fixed contact portion beingdisposed on said major axis of said ellipsoidal casing bore, said buttonmeans of said mechanism having a radially enlarged margin portion with ashape complimentary to the shape of said casing bore means, saidenlarged margin portion being formed with radially extending portionsslidably fitting into said slot means, whereby said slot means serves asa keyway preventing rotation of said button and said actuator means andmounts said upper terminal means.
 11. The mechanism set forth in claim 8wherein said four equal spaced terminal receiving through apertures insaid casing means are each generally of a cross-sectional shapecomplimentary to the shape of the individual said upper and lowerterminal means, each of said through apertures having oppositelydisposed enlarged midportions, at least one individual terminal memberof said upper and lower terminal members having a transverse threadedbore, said threaded bore of said terminal member being aligned with saidcasing aperture enlarged midportion, whereby any burrs on said terminalmembers associated with or formed in the threading of said threadedbores may pass freely through said enlarged midportions without skivingof the margins of said dielectric casing material, the said lowerterminal means of said mechanism being disposed in an oppositelydisposed pair of said through apertures, each of said lower contactmembers having a fixed contact portion for electrical contact with saidcombination switchblade and contact means, said lower terminal meansbeing generally bimetallic first and second members throughout thelength thereof, said first member being substantially one-third of thelower terminal means, an extremely good electrical conductor, andforming the fixed contact portion of the lower terminal means.
 12. Themechanism set forth in claim 6 which assures sequential switchingwherein a pair of combination switchblade and contact means are disposedin pivotally mounted opposed relation on said actuator means forsimultaneous movement between said A and B positions, said mechanismhaving a pair of upper terminal means, a common terminal meanselectrically connected to said actuator means, and a pair of lowerterminal means, each of said lower terminal means having a fixed contactportion located generally transverse to said actuator means and adjacentsaid A position of said combination switchblade and contact means, saidupper terminal means having fixed contact portions in staggeredtransverse relationship vertically above individual contact portions ofsaid lower terminal means, on of said upper terminal means fixed contactportions being disposed closer to said lower terminal means fixedcontact portions than the other of said upper fixed contact portions,whereby movement of said actuator means from its first to its secondposition causes one of said pair of combination switchblade and contactmeans to make mechanical and electrical contact with said one fixEdcontact portion of said upper terminal means before the other of saidpair of combination switchblade and contact means makes mechanical andelectrical contact with said other fixed contact portion of said upperterminal means whereby a sequential switching action is assured.
 13. Theswitch mechanism set forth in claim 6 characterized as a low travelmechanism wherein said tension coil spring has first and second spacedends, said actuator means comprises button means having an exteriorportion and a spring means engaging portion, said spring means engagingportion engaging said tension coil spring at a point along the lengththereof intermediate said spaced first and second ends, said supportmeans comprises bracket means having first and second spaced upstandingportions and a terminal portion, said first portion being formed withthrough aperture means and notch means adjacent said aperture means,said aperture means receiving said tension coil spring and said notchmeans pivotally receiving said spaced leg means of said combinationswitchblade and contact member, said second upstanding portion beingformed with a bracket spring attachment pivot point means for pivotalconnecting receipt of said second end of said tension coil spring, saidfirst end of said tension coil spring being attached to said attachmentstrut means of said combination switchblade and contact member formovement with and for pivotal movement to said combination switchableand contact member, whereby deformation of said tension coil spring bysaid spring means engaging portion of said actuator means causes snapaction movement of said combination switchblade and contact means. 14.The switch mechanism set forth in claim 13 wherein said tension coilspring is the sole biasing force in biasing said combination switchbladecontact means to said A position, exterior pressure on said exteriorportion of said button means causes deformation of said tension coilspring which in turn causes movement of said combination switchblade andcontact means from said A to said B position and release of pressure onsaid exterior portion of said button means causes said combinationswitchblade and contact member to return to said A position solely underthe bias of said tension coil spring.
 15. The switch mechanism set forthin claim 14 wherein the amount of required travel of said button meansnecessary to cause said combination switchblade and contact member tomove from said A position to said B position is a function of thelocation of the point of engagement of said spring engagement meansportion of said button means upon said tension coil spring means alongthe length thereof, the closer the said point of engagement is locatedto said second end of said tension coil spring the greater the requiredtravel of said button means necessary to cause movement of saidcombination switchblade and contact member from said A position to saidB position.
 16. The switch mechanism set forth in claim 6 characterizedas a push-pull mechanism wherein said actuator means when placed in saidA position remains in said A position and when placed in said B positiontends to remain in said B position.
 17. In a compact snap switchmechanism having support means, actuator means movably mounted relativeto said support means for movement from a first position to a secondposition, means for moving said actuator means relative to said supportmeans, and means to return said actuator means from said second positionto its first position, the improvements comprising a pair of discretecombination switchblade and contact means pivotally mounted on oppositesides of said actuator means for movement between A and B positions,said combination switchblade and contact means extending generallytransversally of said actuator means, and spring means connecting saidcombination switchblade and contact means, each of said combinationswitchblade and contact means being characterized as being: a. unitaryone-piece formed metal members having first and second spaced endportions connected by a midportion, b. said first end portion comprisingspaced leg means having means for pivotally engaging said actuatormeans, said spring means extending between said spaced leg means, c.said second end portion comprising, i. a pair of curvilinear spacedcontact portions, one of said spaced contact portions being located inthe plane of said first end and mid portions, the other of said spacedcontact portions being offset from the plane of said first end and midportions, and ii. attachment means for said spring means, saidattachment means being located in a plane which extends from said meansfor pivotally engaging said actuator and an area intermediate saidspaced contact portions, said attachment means being located outwardlyof said actuator means a distance at least as great as the distancebetween said actuator means and said spaced contact portions, saidattachment means affording a pivotal connection to said spring means,whereby movement of said actuator means from said first to said secondposition causes each of said combination switchblade and contact meansto move from said A position to said B position with a snap action andlow bounce of said curvilinear contact portions and upon attainment ofsaid B position, to tend to maintain said curvilinear contact portionsin said B position with high vibrational, shock, and accelerationstability until said actuator means returns to said first position. 18.The switch mechanism set forth in claim 6 characterized as a two polefour circuit mechanism wherein said actuator means comprises anelongated member having a pair of sets of vertically spaced notch meansand a pair of through apertures respectively located adjacent to each ofsaid sets of notch means intermediate the ends of said member saidelongated metal member being further characterized as having aninsulating portion intermediate said spaced sets of notch means andthrough apertures to prevent transmission of electrical current betweenspaced portions of said elongated metal member, said elongated metalmember having a first shoulder means adjacent the top thereof and asecond shoulder means adjacent the bottom thereof, two pairs ofcombination switchblade and contact means, each respective pair havingspaced leg means located in one set of said notch means, bias springmeans associated with said second shoulder means for biasing saidactuator means towards its first position and each of said pairs ofcombination switchblade and contact means toward said A position. 19.The switch mechanism as set forth in claim 18 wherein said actuatormeans includes energy storing means located intermediate said firstshoulder of said elongated member and said button means, said energystoring means comprising a resilient compressible member proportionedand located in the line of force transmission of actuation energypressure on the button means for snap actuation of the combinationcontact and switchblade member, said energy storing means absorbing andstoring part of the energy pressure of actuation for later release, saidenergy storing means releasing the stored energy when one of said pairsof combination switchblade and contact members moves from said A to saidB position, the release of the stored energy assuring that the other ofsaid pairs of combination switchblade and contact means moves from saidA to said B position to thereby assure simultaneity of actuation of bothpairs of combination switchblade and contact means.
 20. In a compactbutterfly snap switch mechanism having support means, actuator meansmovably mounted relative to said support means for movement from a firstposition to a second position, button means for moving said actuatormeans relative to said support means, return bias means having a biasforce of a predetermined magnitude to return said actuator means fromsaid second position to iTs first position, said actuator meanscomprising an elongated member formed with a pair of sets of verticallyspaced notch means and a pair of through apertures located adjacent toeach of said sets of notch means, said elongated member being formed ofmetal and with an insulating portion intermediate said spaced sets ofnotch means to prevent transmission of electrical current between spacedportions thereof, two vertically spaced pairs of switchblade meanspivotally mounted on opposite sides of said actuator means for movementbetween A and B positions, said switchblade means extending generallytransversally of said actuator means, first and second spring meansrespectively extending through said aperture means and respectivelyconnecting said individual pairs of switchblade means in said notchmeans on said elongated member, and energy storing means located in theline of force transmission of actuation energy pressure on the buttonmeans for snap actuation of the switchblade means, said energy storingmeans being a resilient compressible rubber doughnut shaped memberhaving a compressed and an uncompressed state, the force required tocompress said energy storing member from said uncompressed to saidcompressed state being less than said predetermined bias force of saidmeans to return said actuator means from said second position to saidfirst position, said energy storing means absorbing and storing part ofthe energy pressure of actuation for later release, said energy storingmeans releasing the stored energy when one of said pairs of switchblademeans moves from said A to said B positions during movement of saidactuator means from said first to said second position, the release ofthe stored energy assuring that the other of said pairs of switchblademeans moves from said A to said B position to thereby assuresimultaneity of actuation of both pairs of switchblade means.